Slurry concentrator and filter apparatus

ABSTRACT

A slurry concentrator and filter comprises a reservoir for slurry formed with a tapered hopper at the bottom. Stationary pipes extend across the reservoir and carry vertical filter cells having flat screens on opposite sides. A frame structure is movably mounted in the reservoir and carries scraper blades to scrape collected concentrated slurry material from the screens. The frame structure can be arranged to move vertically or horizontally. The frame structure can be reciprocated by a hydraulic cylinder. Spray nozzles can be mounted on the frame structure to wash the screens as the frame structure moves across the screens.

United States Patent Parmentier 1 1 Oct. 2, 1973 [541 SLURRYCONCENTRATOR AND FILTER 170,952 12/1875 Hutchinson 210/334 APPARATUS1,609,265 11/1926 Menge 210/334 1,996,000 3/1935 Horquist 210/334lnvenlorl Alfred Pfll'memler, La 2,609,101 9 1952 Howland et al 210 3341 Bruyere, 3, Lillois, Belgium p 15, Primary ExaminerFrank Spear, .11.Att0rneyPolachek & Saulsbury [21] Appl. No.: 134,149

[57] ABSTRACT [30] Foreign Application Priority Data A slurryconcentrator and filter comprises a reservoir Aug. 11, 1970 Luxembourg61497 for Slurry formed with a tapered pp r t he bott m. Mar. 31, 1971Luxembourg 62884 stationary P p extend across the reservoir and carryvertical filter cells having flat screens on opposite sides. 521 vs. c1210/141, 210/334 A frame Structure is movably mounted in the reservoir[51] Bold 29/38 [58] Field of Search 210/332, 334, 138, 210/141 [56]References Cited UNITED STATES PATENTS 2,368,636 2/1945 Bottaro 210/3341,169,725 1/1916 Kilby 210/334 and carries scraper blades to scrapecollected concentrated slurry material from the screens. The framestructure can be arranged to move vertically or hori-- 3 Claims, 6Drawing Figures PAIENTED T 3.762.551 SHEET 20F 3 2 PUMP LI FIG. 3.

INVENTOR. ALFRED OENRI PARMENTIER W37? A T TURNEYE SLURRY CONCENTRATORAND FILTER APPARATUS I disc filters. ln "this type of filtrationapparatus, the filtering and straining surfaces of the drums and discsare scraped by stationary blades while the drums and discs rotate withrespect to the blades. In some of these filters, water is sprayedfromstationary sprayers upon the filtering surfacesto'c'lean them. lnthisprior type of filtration apparatus only parts of the "filtering surfacesof the drums anddiscs'are'immersed in the slurry 'being strainedand'concentrated. The useful filtration area-is thus about one halforless of the total area of the drums or discs. The rotating drums anddiscs are generally mounted on horizontal drive shafts. This'type ofapparatus has rather complex and'costly constructions. Precisionmachining of partsis'required. The filters are costly to manufacture andservice.

In another prior type of'filtration apparatus enclosed stationarycircular filter members are maintained under pressure and are traversedby scrapers carriedby arotary shaft. This type of apparatus is alsocostly to manufacture and maintain. A difficulty encountered with thisprior apparatusis inefficient'removal of collected solid material fromthe filter members-bythescrapers when the scrapers rotate in a verticalplaneand are in the ascending portion of their rotation cycle.

Another'type of filter apparatus employs cylindrical filter membersmaintained undehpressure iduringthe filtration process. After thefiltrate is removed, the collected solids are removed by injection of awashfluid under pressure in a direction opposite to that in which thefiltratewas drawn through the filter 'members.'This type of apparatussuffers from the disadvantage that the filter members cannot beefficiently cleaned by reverse flow of wash liquid. Also,-it isoften'desirable to restore .moisture' to the solid material after theflfiltrate is removed.-' i v The above and otherdifficultiesanddisadvantages of prior filtration apparatus are avoidedin "the present app'aratus. Here the apparatus-hasflat rectangularfiltration cells of relatively simple, inexpensive construction.Thefiltr'ation cellsare stationary. and mounted'on stationary filterpipes. From time to 'time collected solids fromthe filtered slurry areremoved by scrapers which' loosen the solid material so that it falls tothe bottom of a filter tank or reservoir from whichthe s'olid materialor concentrated slurry is removed: ln the present in vention,'the entirescreening or straining area of the filter cells is always whollyimmersed in the'slurry being filtered. The apparatus can-operatecontinuously, with filtrate being constantly'removed, whilefresh slurryis fed to the apparatus. Periodically the screening areas or surfacesare scraped clean by scrapers carried by a simple moving framestructure. The apparatus can be drained periodically and thescreeningareas can be flushed with a washing liquid ejected by'spraying nozzlescarried by the" mov'ingframe'structure; The washing liquid is sprayedonly during movement 'of the frame structure. The consumption of washingliquid is minimized and the concentration of slurry is maximized. Theapparatus is arranged so that filtration and concentration of slurry canbe continuous or can be performed discontinuously on predeterminedquantities of slurry.

The apparatus is particularly well adapted for use in paper mills whereslurries containing fillers, glue, wax, resin and other colloidalmaterials can be concentrated and removed from the slurries. Theapparatus is adapted for automatic control and preprogrammed au tomaticoperation.

Other and further features, objects and advantages of the invention willbecome apparent from the following detailed description taken togetherwith nying drawings, wherein: I FIG. 1 is atop plan view of a slurryconcentrator and the accompafilter embodying the invention, parts beingbroken away to show internal construction.

FlG. 2'is a vertical cross sectional view taken onz'line 22 of FIG. 1.

FIG. 3 is a vertical longitudinal sectional view-taken on-line 3-3of'FlG. l.

FIG. 4 is an enlarged fragmentary cross sectional view similar to aportion'ofFlG. '2,'illustrating amodification of the invention. I

'FIGVS'is afragmentary longitudinal cross sectional view similartoa.-portion of' FIG. 3, takenonlines 5-5 of FIG. 4. v

FIG. 6 is a diagrammatic representation of another slurry concentratorand filter shownin' longitudinal vertical section similarto FlG. 3.

Referringfirst'to FIGS. 1-3, there is shown a slurry concentratorandfilter including a tank or reservoir 10 having vertical end walls11,12, vertical sidewalls-13,

holes 26 at upper sides. A pair of filtercells 28, 30 are in'stalled'oneachpipe 24.

Each filter cell comprises a rigid: rectangular frame formed -byhorizontal bars-32,33 at the top and bottom and vertical sidebars34.=-Opposite vertical sides of each frame is covered bya foraminousfilter screen 36 which may be a clothmesh, metallic or plasticscreening, or the-likehThe bottom bars 33are formed with holes38registering with'the holes 26 in pipes 24.'Resilient sealing gaskets 40areinterposed between the bars '33-and pipes 24, and providedwith.holesregistering -with.holes 38-and 26." Each pair of cells. 28, 30isdisposed-in a vertical coplanar, positionflon each pipe 24.

The cells on each pipe are laterally spaced from adjacent cells onadjacent pipes 24. I

"In order to hold'the cellstightly on pipes 24, there is provided a'pairof beams 44 mounted on the end walls 11, l2, and carrying clampingbrackets 46. These I brackets support horizontal; bars 48, each of whichis aligned with and extends over an alignedp'air of cells 28;30uBars48overlay the. upper bars 32 of'the cell frames: The clamping brackets 46include bolts 49 ,ancl

nuts50 which are tightened to press bars 48 firmly down on cells 28,30-.-Brace bars 5l-having threaded ends secured by nuts 53 at pipes 24and bars 48 strengthen the cellmounting structure. Each cell is thusrendered stable and stationary in the reservoir by supporting pipes 24and beams 22, 23 at the bottom, and by beams 44, clamping brackets 46and bars 48 at the top and brace bars 51 between the pipes 24 and bars48.

The pipes 24 are connected by conduits 52 outside the reservoir tomanifold pipes 54 at opposite ends of the reservoir. These manifoldpipes can be connected to individual pumps 55 or to single pump fordrawing liquid filtrate from the slurry in the tank. The slurry can befed into the tank from a supply thereof via a pipe 56 connected to adischarge pipe 58 via a float valve 60. This valve has a buoyant ball 62which rises and cuts off the flow of slurry into the reservoir when itreaches a predetermined level L (H6. 3).

The concentrated, viscous material which collects on the parallelvertical filter screens 36 can be removed by scraping by means which isnow described. A frame structure 70 is mounted in the reservoir 10. Thisframe structure includes two upper horizontal transversely extendingcross bars 72 and two lower transverse bars 74 spaced apartlongitudinally of the reservoir 10. Bars 72 and 74 are perpendicular tothe cells 28, 30. The upper bars 72 are connected together by horizontallongitudinally extending upper girders 76, 77 and lower bars 74 areconnected by horizontal bars 78. Between bars 72 and 74 are securedvertical slats 80 which extend between the cells parallel to andequidistant from screens 36 on both sides of cells 28, 30. The slats 80carry scraper blades 82 which may be rigid or flexible. The bladesextend the full lengths of screens 36 and scrape the screens when theframe structure 70 is moved longitudinally of the reservoir in adirection parallel to cells 28, 30.

The frame structure is moved by a horizontal piston rod 84 extendingaxially outward of a hydraulic drive cylinder 86. Rod 84 extends througha packing ring 88 in end wall 12 of the reservoir. The frame structureis movably supported by two pairs of stationary horizontal channelshaped tracks 90 secured between the end,

walls 11, 12 on mounting plates 91. On these tracks roll carriagescomprising wheels 92 engaged on cross axles 94. The axles extend throughvertical carriage plates 96 secured to and extending upwardly fromgirders 76, 77. Wear resistant smooth spacer blocks 98 on upper sides ofgirders 76, 77 prevent vertical and lateral movement of the framestructure 70 as it is carried along by the wheels 92 on tracks 90. Toeach lower bar 78 are attached depend-ing guide plates 99 provided withinner wear resistant spacer blocks 101 sliding along stationaryhorizontal guide rails 102 mounted between end walls 11, 12. Rails 102are parallel to and disposed in the same vertical planes as upper tracks90.

The hydraulic cylinder reciprocates piston rod which moves the framestructure 70 through the entire longitudinal width of cells 28, 30 sothat the entire surfaces of screens 36 are scraped by blades 82. Theframe structure can be reciprocated one or more times during eachfiltration cycle to scrape concentrated slurry mud from the screens.This mud will fall to the bottom hopper 16 and will be drawn off by pump20. The water or other liquid content of the slurry is drawn off bypumps 55 applying suction through pipes 54, 52 and 24 in turn. Theslurry is strained by the filter screens so that a clear filtrate passesinto pipes 24. If desired, the frame structure 70 can be held stationaryuntil a desired quantity of liquid has been strained from the slurry.

The remaining concentrated on the screens 36 can then be scraped off byblades 82 while the frame structure is moved back and forth one or moretimes.

A number of modifications of the basic structure illustrated in FIGS.1-3 and described above can be made. For example, any desired number offiltration cells can be installed on pipes 24. There can be a singelcell on each pipe, two cells as shown in the drawings or more than twocells. The moving frame structure will be provided with one scraperblade 82 for each longitudinal line of filter screens 36. If desired,the cells can be divided into groups, with a separate movable framestructure 70 for scraping each group of cells. A single hydrauliccylinder or jack 86 can be arranged to move all frame, or a separatecylinder can be provided for each movable frame structure. it is alsopossible to provide hydraulic cylinders 86 at opposite ends of thereservoir, with one cylinder arranged to move the frame structure in onedirection and the other cylinder arranged to move the frame structure inthe opposite direction.

It is possible to employ the apparatus for continuous concentration ofslurry, by continuously draining off liquid while fresh slurry is fedinto the reservoir via inlet pipe 58. The apparatus can also be used toconcentrate a single charge of slurry at a time. To do this the slurrywill be fed into the reservoir until level L is reached. The supply ofslurry will then be shut off at the source thereof and filtration canthen start by operating pumps 55. When the desired quantity of liquid isremoved, the solid caked material collected on screens 36 can be scrapedoff. It will be apparent therefore that the apparatus can serve as acontinuous slurry concentrator, or as a filtering device for separatecharges of slurry.

In some installations it may be desirable to wash the screens 36 aftereach filtration cycle or after a number of such cycles. For this purposethe arrangement of FIGS. 4 and 5 can be used. On cross bars 72 of framestructure 70 are mounted brackets 110 carrying spray nozzles 112 towhich flexible pipes 114 are connected. Pipes 114 are connected to asupply of washing liquid which will be fed at high pressure. The nozzles112 will direct sprays of washing liquid on the screens to clean themwhile the frame structure 70 is moved back and forth with respect to thefiltration cells 28, 30. it will be noted that the nozzles 112 arearranged in pairs at opposite sides of the cells and at opposite sidesof each scraper blade 82. There is a pair of nozzles at opposite uppercorners of each screen 36.

The frame structure 70 as shown in FIGS. l-5 is arranged to movehorizontally. It is possible to arrange the frame structure to movevertically. This is indicated diagrammatically in H6. 6 where the framestructure 70a moves vertically on vertical tracks 76a and vertical guiderail 77a supported by end walls 11a, 12a of reservoir or tank 10a. Theframe structure includes horizontal bars a which carry horizontalscraper blades 82a. The blades move vertically with the frame structureto scrape screens 36 of filter cells 28, 30. The reciprocating cylinder86a mounted above the tank on support 86'. Axially vertical piston rod84a is connected to upper bars 80b of the frame structure.

Suitable auxiliary control apparatus of conventional type includingcontrol valves, switches and the like will be provided for operating theseveral pumps, slurry supply and hydraulic cylinder of the apparatus.The control apparatus can be arranged to operate automatically toperform a timed, programmed filtration cycle.

The filtration apparatus shown in the drawings and described above makesit simple and convenient to clear and clean large filtration areas, inan apparatus of minimum size. The apparatus is relatively simple inconstruction, easy to operate, relatively inexpensive to install andmaintain.

I claim:

1. A slurry concentrator and filter apparatus, comprising a reservoirhaving vertical walls and closed bottom for containing a quantity ofslurry to be filtered and concentrated; a plurality of horizontal pipesdisposed in laterally spaced positions and extending between oppositewalls of the reservoir just above the bottom thereof, said pipes havinga plurality of spaced holes formed in upper sides thereof; a pluralityof filter cells respectively mounted on said pipes, each of said cellscomprising a generally rectangular frame with flat, rectangular filterscreens applied to opposite sides of the frame, said frame having bottomopenings registering with the holes in the pipes on which the filtercell is mounted; means for supporting the cells in vertical positions onthe pipes with said screens disposed in spaced vertical planes parallelto axis of the pipes; automatic cyclic means for cyclically drawingliquid from the slurry automatically repeatedly through said cells andpipes, for concentrating the slurry on said screens;

means supporting a plurality of straight scraper blades in paralleldisposition in the reservoir with scraping edges of the bladesvertically disposed in the planes of the respective filter screens;means for said blades simultaneously horizontally moving across thescreens and remove concentrated slurry material therefrom; a movableframe structure in the reservoir carrying said blades and the means formoving the blades comprising automatic mechanical reciprocation meansconnected to the frame structure to move the blades across the screensin opposite directions cyclically automatically alternately withcontinual filtering cycles; and a water spray means arranged on oppositesides of the screens and mounted on said frame structure for movementwith the blades to spray washing liquid on the screens while the bladesscrape the screens.

2. A slurry concentrator and filter apparatus as defined in claim 1,wherein the bottom of the reservoir is tapered to define a hopper sothat the material scraped from the screens falls into the hopper; andmeans for removing the material collected in the hopper.

3. A slurry concentrator and filter apparatus as defined in claim I, inwhich said spray means includes a plurality-of water spray nozzlesarranged on opposite sides of the screens.

1. A slurry concentrator and filter apparatus, comprising a reservoirhaving vertical walls and closed bottom for containing a quantity ofslurry to be filtered and concentrated; a plurality of horizontal pipesdisposed in laterally spaced positions and extending between oppositewalls of the reservoir just above the bottom thereof, said pipes havinga plurality of spaced holes Formed in upper sides thereof; a pluralityof filter cells respectively mounted on said pipes, each of said cellscomprising a generally rectangular frame with flat, rectangular filterscreens applied to opposite sides of the frame, said frame having bottomopenings registering with the holes in the pipes on which the filtercell is mounted; means for supporting the cells in vertical positions onthe pipes with said screens disposed in spaced vertical planes parallelto axis of the pipes; automatic cyclic means for cyclically drawingliquid from the slurry automatically repeatedly through said cells andpipes, for concentrating the slurry on said screens; means supporting aplurality of straight scraper blades in parallel disposition in thereservoir with scraping edges of the blades vertically disposed in theplanes of the respective filter screens; means for said bladessimultaneously horizontally moving across the screens and removeconcentrated slurry material therefrom; a movable frame structure in thereservoir carrying said blades and the means for moving the bladescomprising automatic mechanical reciprocation means connected to theframe structure to move the blades across the screens in oppositedirections cyclically automatically alternately with continual filteringcycles; and a water spray means arranged on opposite sides of thescreens and mounted on said frame structure for movement with the bladesto spray washing liquid on the screens while the blades scrape thescreens.
 2. A slurry concentrator and filter apparatus as defined inclaim 1, wherein the bottom of the reservoir is tapered to define ahopper so that the material scraped from the screens falls into thehopper; and means for removing the material collected in the hopper. 3.A slurry concentrator and filter apparatus as defined in claim 1, inwhich said spray means includes a plurality of water spray nozzlesarranged on opposite sides of the screens.